Basic Concepts

Contents

• Basic Concepts
  • Introduction
  • Class
  • Object
  • Entity
  • Identifiers
  • Methods

Introduction

This page contains basic concepts for users working with SOZ-LIVE.

Class

A Class is a template for the creation of an Object.
Everything that is created in CAD, and in SOZ, is an Object of a particular Class.
This includes graphical entities such as:

• AcDbLine - a 3d Line entity - between two points.
• SZCEPart - a complex derived entity containing Features, to define a parametric 3d Enitity.

Through to non-graphical objects such as:

• SZLPReal - a value object for a real number.
• SZLPReals - a value object for a list of Real Numbers.

Note:
- Except for Lisp values, each class has a four letter prefix that identifies it as belonging to a particular part of the class hierarchy.
- Refer to the Prefixes document for details.

Object

Within SOZ-LIVE an Object is the base level of things created.

They are non-graphical in nature and range from simple values such as:

• Real - a Lisp real number
• Boolean - a value that is either True or False.

Through to complex geometric objects that utilise other objects and entities in their calculated value(s):

• SZGEPoint-AcDbCircle-Center object - that returns the center Point of a AcDbCircle Entity.
• SZGEPattern2D-Rectangular object - that creates and returns a list of TMatrix values for the insertion of Entities into the Model in a Rectangular 2D Pattern.

Note:
- A Real value entered into a dialog box is stored as a string until required by the program.
- This enables lisp equations such as (/ 1.0 3.0) to be entered and calculated to full precision as and when required.

Entity

Within SOZ-LIVE an Entity is derived from Object and describes Objects that are graphical in nature.

Base entity classes predominantly begin with the prefix AcDb, and derived classes are typically prefixed with SZCE.

Identifiers

All objects in SOZ are stored and passed by reference to an ID - that is a string incorporating the object’s Handle.
eg: "#O#AA5" would be the SOZ object with the handle AA5.

Note:
- All Make routines return the ID of the object / entity that was created.

Method

Within SOZ each function is defined as a Method of a particular Class.

When interacting with SOZ you are basically manipulating Objects by applying a method to the Object.